cold air inside cab?

I bought a used 2000 2500 silverado with I love but this winter I discoved that cold outside air is coming inside passenger side of the cab any idea where the cold air is coming from? the climate controls have no affect on the cold air. almost seems like there is a hole in the firewall but don't see one the air comes in at your feet have to put blanket on my feet to keep from getting so cold

I have the same problem with my 2001 2500. The cold air is coming from behind the glove compartment. If you run your hand along the plastic heater housing behind the glove compartment you can feel the incoming air. The Chevy garage said it could be a bad seal in the duct work. My warrenty has run out since I brought it to their attention after last winter. It was warmer when I took it in and the air was not that noticable. I'm going to take it back soon and I hope they have a record of my first complaint and will fix it under warranty

I took my 2001 Siverardo in yesterday and the new service manager knew exactly what the problem was. The mis-positioned foam seal per bulletin #01-01-37-008. They corrected it and I could tell an immediate improvemnt in comfort on the drivers side and I'm sure my wife will notice the improvement even more!